Barcelona midfielder Ibrahim Afellay has undergone an operation on his damaged knee and will be sidelined for around six months.

The European champions announced the news on their official website this evening, with doctors confirming Afellay would remain in hospital for three to four days before beginning his rehabilitation.

Afellay tore the anterior cruciate ligament in his left knee during training on September 22 and the Holland international had reconstructive surgery this afternoon.

The 25-year-old, who joined Barcelona from PSV Eindhoven in January, had only just got back into Pep Guardiola's line-up after missing the start of the Primera Division season due to a hamstring injury.